CO2 Removal

If the DO removal of X-40 and X-50 fibers are identical and X-50 fiber is better suited for CO2 removal, then why not have only one product – X-50?
The answer to this question relates to another property of fibers called porosity. Porosity is basically defined as the number of pores for a given amount of surface area. In order to process CO2 in the large volumes often required, a more porous membrane is required. A more porous membrane allows more gases to be removed. However, water vapor can also pass through the membrane pores during this process. The drawback to a more porous membrane is that increased amounts of water vapor are also passed through the membrane. While not excessive, this water vapor must also be processed by the other equipment in the degassing system and the additional water vapor load must be accounted for in the vacuum portion of the design. This requires increased vacuum pump capacity. Therefore, using X-40 fiber can provide a more economical system design because a smaller vacuum pump can be used.

Ink Jet Ink and Coating Debubbling

What is the range of vacuum required for proper 0.5x1 SuperPhobic MicroModule operation?
A small vacuum pump capable of pulling ~50-150 Torr (~1-2acfm air) will suffice. The deeper the vacuum, the more efficient the O2 removal. It is important to not pull vacuum beyond the limits of the most volatile solvent in the ink.

Do you recommend plugging the second vacuum port, leaving it open, or drawing vacuum from both vacuum ports?
Either way yields about the same results. For applications with space limitations, one end should be plugged.

How viscous of a solution can a SuperPhobic Contactor tolerate?
UV curable inks and coating solutions with viscosities as high as 4,000cp have been degassed using SuperPhobic Contactors.

Will the ink penetrate through the membrane into the pump?
Typically no. It is important to not pull vacuum beyond the limits of the most volatile solvent in the ink.

Which SuperPhobic Contactor is right for me?
The contactor size is determined by the flow rate. This information is available on the data sheet for each contactor.

Do I need a contactor for each ink?

What is the priming volume of the contactor?
The priming volume is different for each contactor. This information is available on the data sheet for each contactor.

How do you test ink degassing efficiency?
Most customers test by observation and print quality. A special probe capable of measuring dissolved gasses can be purchased from third party sellers, however, these meters and probes can be quite expensive.


What are the most common applications?
- Oxygen removal (<1ppb is easily achieved)
- Carbon dioxide removal (1 ppm is easily achieved)
- Nitrogen removal
- Humidification of gasses
- Debubbling water, inks, emulsions, developers
- Hydrogenation
- Nitrogenation
- Carbonation

Are Liqui-Cel® Membrane Contactors really economical compared to other oxygen removal technologies?
As with any purchase, you should evaluate the "cost of ownership" of each technology. Modularity, stable operation, minimal instrumentation, and no chemical introduction are all attributes of Liqui-Cel Membrane Contactors that can save you time and money. The capital and operating cost will depend on your specific needs. Generally, Liqui-Cel Membrane Contactors will be more economical than a vacuum tower, catalytic system, and some forced draft degasifiers. Chemical scavenging and steam deaerators are tough competitors, but you should evaluate Liqui-Cel Technology as an option to fully understand your alternatives.

What about Liqui-Cel® Membrane Contactor economics for CO2 removal?
Liqui-Cel Membrane Contactors offer great advantages over conventional technology when removing CO2 at medium flow rates or when removal of O2 is done at the same time. At large flow rates, the economics are case dependent on customer needs. Liqui-Cel Membrane Contactors are the only cost effective technology capable of removing CO2 down to 1 ppm without introducing any contaminates (including oxygen) to your pure water stream. We also commercialized a new 6-inch product variant in 2001 that was designed to meet the economic requirements of  CO2  removal applications. Many customers have taken advantage of Liqui-Cel Membrane Contactor modularity by splitting the degasification processes and using the first bank of contactors to remove CO2 and some O2, and using the second bank of contactors to remove O2 to very low levels.

Are Liqui-Cel® Membrane Contactors able to withstand free chlorine? What about ozone?
Liqui-Cel Membrane Contactors are compatible with free chlorine at pH > 7, a concentration not higher than 100 ppm, limited exposure time and ambient temperature. The following formula will give you the maximum exposure time when the contactor is exposed to Cl2. Max. Exp. time (hr) = 26000 / actual Cl2 concentration (ppm). If the contactor is overexposed, fibers will start loosing their mechanical properties. Ozone at concentrations above ppt levels is NOT COMPATABLE with Liqui-Cel Membrane Contactors.

What do the numbers 4x28, 10x28, etc. mean?
These numbers represent the approximate dimensions of the cartridge that is inside the housing of the Liqui-Cel Membrane Contactor. The cartridges vary in dimension based on the product capacity. For example, 4x28 would indicate a 4 inch diameter cartridge that is 28 inches long.

What are the basic differences between the X-40 and X-50 fibers?
These numbers identify the type of membrane used for gas removal from water. Each fiber type has been designed with unique properties that maximize gas removal efficiency. For example, X-40 fiber is best suited for dissolved oxygen (DO) removal from water. However, because most CO2 removal applications require significantly larger volumes of gas removal than DO removal applications, the X-50 was developed with a larger fiber ID to allow more gas to sweep through the fiber. Therefore, the X-50 fiber is the better choice for carbon dioxide (CO2) removal from water.

Is there a proper flow direction for the liquid?
Liquid flows on the shell side of the device for all extra-flow membrane contactors of 2.5-inch diameter and larger. It does not matter which shell side port is selected as the inlet. The key is that the gas flow through the fiber should be counter-current to the liquid flow.

What connections are available on the Liqui-Cel Contactors?
Each contactor has various connection options. Please refer to the Liqui-Cel datasheet for the specific connections available on each product.

How do I determine which Liqui-Cel Contactor is right for me?
The flow rate and the specific application are used to determine the size and type of contactor required.

How do I determine which fiber is right for my application?
X-40 fiber is typically used for O2 removal. X-50 fiber is used for CO2 and all other gas removal. X-40 fiber is also used for carbonation or other gasifying applications.

Where can I find references of similar systems from other customers?
References can be requested from your sales representative. There is also find a list of installations online at

Where can I find a general system design or P&ID for a complete Liqui-Cel system?
Generic system designs are available. Contact your sales representative or locate these designs online at

What can I use to clean my Liqui-Cel Contactor?
Please review the Cleaning Guide. It can be found online at

What is the maximum temperature tolerance of a Liqui-Cel contactor?
Each contactor has a different operating pressure and temperature maximums. This information is available on the datasheet for each contactor and in the Operating Guide.

How do I start my Liqui-Cel Contactor system?
Refer to the Start-up Guide for your specific product. Additional information is also located in the full operating guide for contactors 2.5x8-inch and up.

Why is vertical mounting preferred over horizontal mounting?
Vertical mounting allows for contactors to be drained properly for storage when not in operation. Horizontal mountings are only recommended for continuous flow systems that will not be shut down for any significant time.

What is the preferred mounting orientation for Liqui-Cel Contactors?
Vertical mounting is recommended for optimal draining. See Operating Guidelines for special notes if horizontal mounting is preferred for your application.

How will I know if my Liqui-Cel Contactor is not working properly?
If the contactor is not degassing properly then there may be a deficiency in gas removal, an increase in pressure drop across the contactors and possibly leaks in the contactor.

What would cause leaks in the membrane?
A leak could be the result of the wetting out of the membrane, oxidized fibers, or leaks in the seals or potting.

What chemicals are safe and what should be avoided in a Liqui-Cel or SuperPhobic Membrane Contactor?
A Chemical Resistance Guide is available that displays a number of chemicals that are tolerated in a Liqui-Cel Membrane Contactor. This guide can be found online at

What are the reasons Liqui-Cel Membrane Contactors would need to be replaced?
Oxidized fiber or irremovable particle fouling are typical reasons a Liqui-Cel Membrane Contactor would need to be replaced.

What are the benefits of a Liqui-Cel Membrane Contactor over existing technologies?
Liqui-Cel Membrane Contactors are safer and cheaper than chemical dosing. These devices can be prefabricated and skid mounted for easy building and moving. They are an in-line solution where an additional recirculation pump is not required. These features, along with minimal power costs, make them more economical than conventional methods. Reduced blow down time and ease of cleaning are additional benefits that a Liqui-Cel Membrane Contactor system has over other degassing methods. Liqui-Cel Membrane Contactors also have a short lead time.

How much does a Liqui-Cel Contactor cost?
Each contactor is priced differently and prices vary by quantity ordered. Contact a Liqui-Cel representative to size a system for your application and to obtain cost and availability.

Who do I contact for assistance regarding my Liqui-Cel Contactor?
Contact our Sales and Technical Support Team at (704) 587-8888.

Can I remove carbon fouling from my Liqui-Cel Contactor?
Some of the carbon can likely be removed, but not all. Backflushing should be used to clean the contactor. A cleaning guide is available at

Do you provide technical service and onsite service?
Yes. Sales and technical service representatives are available. On-site training and technical service is available for a small fee.

How do I change out the cartridge in my Liqui-Cel Contactor?
See the Assembly/Disassembly guides at

What do I need to replace when I change out the cartridge in my Liqui-Cel Contactor?
Replacement of the cartridge and o-ring is typically recommended. Tool kits are available for this procedure. Refer to the change out guide for your contactor for specific replacement instructions and a description of the tools.

O2 Removal

Can a Liqui-Cel Membrane Contactor with X-50 fiber be used for dissolved oxygen (DO) removal?
The DO removal efficiency for X-40 and X-50 fiber is identical. Either device will work for DO removal.

What minimum concentration of O2 can you obtain with a Liqui-Cel Contactor?
Liqui-Cel Contactors can remove O2 to 1ppb.

What kind of system do you recommend for O2 removal?
A Liqui-Cel Contactor with X-40 fiber is recommended. The system can be designed to operate with vacuum only or combo vacuum with a nitrogen sweep for ultra pure water.


Can I remove ammonia without adjusting to a higher pH?
Yes, but the removal will be low.

System Building

Will CO2 removal damage my vacuum pump?
There can be some corrosion in the liquid ring vacuum pump due to pH shift with CO2 removal. A liquid ring vacuum pump with stainless steel wetted parts is recommended for high levels of removal. For moderate to low levels a standard liquid ring pump with a cast iron impellor may be more economical. The cost of a pump with stainless steel wetted parts is about double that of the standard pump.

Do I really need everything in the P&ID?
The P&IDs are recommended system designs intended only to provide a guideline. They include various elements that facilitate troubleshooting and promote safety.

What kind of prefilter do I need prior to my Liqui-Cel Contactor?
A 5-10 micron filter on the liquid side will suffice. A 3 micron filter is recommended for the gas inlet.

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